PROJECT SUMMARY One of the most difficult problems facing drug abuse practitioners is the continuing high rate of relapse following treatment. While there are multiple internal states and external cues that may trigger relapse, one common factor is to re-associate with drug-using social peers. Although some recent preclinical work has examined the role of social influence on acquisition and maintenance of drug self-administration, there is essentially no information about the role of social cues in reinstatement of drug seeking. The overall hypothesis of this project is that self-administering social peers will serve as a cue to induce drug seeking in a controlled preclinical laboratory setting. Separate from discrete cues (light, tone) and contextual cues (tactile and visual cues, time of day), these studies will determine if social peers also are able to reinstate extinguished responding for drug. In addition, these studies will provide definitive information about the potential interactive effects of social and contextual cues in reinstatement. Two specific aims are proposed. First, we will determine if there are sex differences in discriminative social cue-induced reinstatement and if social cues potentiate the ability of contextual cues to reinstate drug seeking. Second, in these of behavioral experiments, c-Fos protein immunoreactive cells will be quantitated in various brain regions to determine if neural activation following social cues differs between males and females or if activation by social cues differs from contextual cues. If social cues prove to be a trigger for drug seeking, this would provide evidence that informs psychosocial treatments which emphasize skill-building to avoid deviant peers.